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Antiplatelet Therapy in Patients With Abdominal Aortic Aneurysm Without Symptomatic Atherosclerotic Disease
Chalotte W Nicolajsen1,2,3, Mette Søgaard1,2, Martin Jensen1
1Department of Cardiology, Aalborg University Hospital, Aalborg, Denmark.
Insights
Antiplatelet therapy showed no significant benefit in reducing ischemic events for patients with abdominal aortic aneurysms. The study indicated a potential trend toward increased bleeding risk, suggesting limited clinical relevance for this treatment in this population.
Area of Science:
- Cardiovascular Medicine
- Clinical Epidemiology
- Pharmacology
Background:
- Patients with abdominal aortic aneurysms (AAA) face high ischemic event risk due to comorbid atherosclerotic cardiovascular disease.
- Current guidelines recommend antiplatelet therapy for AAA patients, but its benefit in those without symptomatic atherosclerosis is under-researched.
Purpose of the Study:
- To evaluate the efficacy of antiplatelet therapy in preventing ischemic events and bleeding in individuals with AAA but no symptomatic atherosclerotic vascular disease.
- To provide evidence-based insights for clinical practice regarding antiplatelet use in this specific patient group.
Main Methods:
- A comparative effectiveness study using target trial emulation on Danish national health registry data.
- Inclusion criteria: antiplatelet-naive patients diagnosed with AAA without symptomatic atherosclerotic vascular disease (2010-2021).
- Outcomes assessed: ischemic events (myocardial infarction, ischemic stroke) and major bleeding, analyzed using pooled logistic regression.
Main Results:
- Analysis included 6,344 patients; 3,363 initiated antiplatelet therapy. Intention-to-treat analysis showed no significant reduction in ischemic events (HR 0.91; 95% CI, 0.73-1.17).
- A trend towards increased bleeding risk was observed with antiplatelet therapy (intention-to-treat HR 1.26; 95% CI, 0.97-1.58).
- The absolute differences in event rates between groups were minimal, suggesting limited clinical significance.
Conclusions:
- Antiplatelet therapy did not demonstrate effectiveness in lowering ischemic event risk among patients with AAA and no symptomatic atherosclerotic vascular disease.
- A potential increase in bleeding risk was noted, and the overall clinical relevance of antiplatelet treatment in this population appears limited.
- Further research may be warranted, but current findings suggest a cautious approach to prescribing antiplatelets in this subgroup of AAA patients.
Importance:
Patients with abdominal aortic aneurysm have a high risk of ischemic events associated with concomitant atherosclerotic cardiovascular disease, and current clinical practice guidelines recommend antiplatelet therapy to mitigate this risk. However, in patients with aneurysms without symptomatic atherosclerosis, the benefit of antiplatelet therapy has been sparsely investigated.
Objective:
To estimate the effect of antiplatelets on the risk of ischemic events and bleeding in individuals with abdominal aneurysms with no symptomatic atherosclerotic vascular disease.
Design, Setting, And Participants:
A comparative effectiveness research study using a target trial emulation framework was performed. Population-based, cross-linked observational data from Danish national health registries containing comprehensive, individual-level information on all Danish citizens were used to evaluate patients who were antiplatelet-naive and diagnosed with abdominal aortic aneurysms, with no record of symptomatic atherosclerotic vascular disease, from January 1, 2010, through August 21, 2021.
Exposure:
Prescription filled for aspirin or clopidogrel.
Main Outcomes And Measures:
Risk of ischemic events (myocardial infarction and/or ischemic stroke) and risk of major bleeding. For target trial emulation, trials were emulated as sequential, contingent on patient eligibility at the time of inclusion, and were evaluated by means of pooled logistic regression models to estimate the intention-to-treat and as-treated effects, expressed as hazard ratio (HR) and event-free survival.
Results:
A total of 6344 patients (65.2% men; age, 72 [IQR, 64-78] years) provided 131 047 trial cases; 3363 of these cases involved initiation of antiplatelet therapy and 127 684 did not. A total of 182 ischemic events occurred among initiators and 5602 ischemic events occurred among noninitiators, corresponding to an intention-to-treat HR of 0.91 (95% CI, 0.73-1.17) and an estimated absolute event-free survival difference of -0.6% (95% CI, -1.7% to 0.5%). After censoring nonadherent person-time, the treatment HR was 0.90 (95% CI, 0.68-1.20), with similar risk difference. For bleeding, the intention-to-treat HR was 1.26 (95% CI, 0.97-1.58) and the event-free survival difference was 1.0%. The treatment HR was 1.21 (95% CI, 0.82-1.72); the risk difference was similar.
Conclusions And Relevance:
In this study, no evidence of effectiveness of antiplatelet therapy to lower the risk of ischemic events and a trend toward higher bleeding risk was noted. The observed differences between the treatment groups were minimal, suggesting limited clinical relevance of antiplatelet treatment.
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